docs: def launch(self, tunnelPorts=None):
          """Launch every worker assigned on this host."""
          if self.isLocal():
              # Launching local workers
              c = self._getWorkerCommandList()
              self.subprocesses.append(subprocess.Popen(c))
          else:
              # Launching remotely
              BASE_SSH[0] = self.ssh_executable
              sshCmd = BASE_SSH if not self.rsh else BASE_RSH
              if tunnelPorts is not None:
                  sshCmd += [
                      '-R {0}:127.0.0.1:{0}'.format(tunnelPorts[0]),
                      '-R {0}:127.0.0.1:{0}'.format(tunnelPorts[1]),
                  ]
              self.subprocesses.append(
                  subprocess.Popen(sshCmd + [self.hostname, self.getCommand()],
                                   bufsize=-1,
                                   stdout=None,
                                   stderr=None,
                                   stdin=subprocess.PIPE
                  )
              )
  
          return self.subprocesses